Chef became a mod just recently.
I don't want a member who bumps threads for no reason but I'm stuck with Glorb.
But I will agree, in this case I don't personally think locking the thread was necessary. I'm not going to undermine Chef and unlock it, but you have to realize it's a judgment call on the part of the mod/admin.
If you actually want to know why something was done, ask them instead of criticizing.